Concerted versus stepwise mechanisms of cyclic proton transfer:Experiments, simulations, and current challenges

Proton transfer(PT) is a process of fundamental importance in hydrogen(H)-bonded systems. At cryogenic or moderate temperatures, pronounced quantum tunneling may happen due to the light mass of H. Single PT processes have been extensively studied. However, for PT involving multiple protons, our understanding remains in its infancy stage due to the complicated interplay between the high-dimensional nature of the process and the quantum nature of tunneling. Cyclic H-bonded systems are typical examples of this, where PT can happen separately via a “stepwise” mechanism or collectively via a “concerted” mechanism. In the first scenario, some protons hop first, typically resulting in metastable intermediate states(ISs) and the reaction pathway passes through multiple transition states. Whilst in the concerted mechanism, all protons move simultaneously, resulting in only one barrier along the path. Here, we review previous experimental and theoretical studies probing quantum tunneling in several representative systems for cyclic PT, with more focus on recent theoretical findings with path-integral based methods. For gas-phase porphyrin and porphycene, as well as porphycene on a metal surface, theoretical predictions are consistent with experimental observations, and enhance our understanding of the processes. Yet, discrepancies in the PT kinetic isotope effects between experiment and theory appear in two systems,most noticeably in water tetramer adsorbed on NaCl(001) surface, and also hinted in porphycene adsorbed on Ag(110)surface. In ice Ih, controversy surrounding concerted PT remains even between experiments. Despite of the recent progress in both theoretical methods and experimental techniques, multiple PT processes in cyclic H-bonded systems remain to be mysterious.

Effects of acute kidney injury on acute pancreatitis patients’ survival rate in intensive care unit: A retrospective study

BACKGROUND Acute kidney injury(AKI)is one of the most common acute pancreatitis(AP)-associated complications that has a significant effect on AP,but the factors affecting the AP patients’survival rate remains unclear.AIM To assess the influences of AKI on the survival rate in AP patients.METHODS A total of 139 AP patients were included in this retrospective study.Patients were divided into AKI group(n=72)and non-AKI group(n=67)according to the occurrence of AKI.Data were collected from medical records of hospitalized patients.Then,these data were compared between the two groups and further analysis was performed.RESULTS AKI is more likely to occur in male AP patients(P=0.009).AP patients in AKI group exhibited a significantly higher acute physiologic assessment and chronic health evaluation II score,higher Sequential Organ Failure Assessment score,lower Glasgow Coma Scale score,and higher demand for mechanical ventilation,infusion of vasopressors,and renal replacement therapy than AP patients in non-AKI group(P<0.01,P<0.01,P=0.01,P=0.001,P<0.01,P<0.01,respectively).Significant differences were noted in dose of norepinephrine and adrenaline,duration of mechanical ventilation,maximum and mean values of intra-peritoneal pressure(IPP),maximum and mean values of procalcitonin,maximum and mean serum levels of creatinine,minimum platelet count,and length of hospitalization.Among AP patients with AKI,the survival rate of surgical intensive care unit and in-hospital were only 23%and 21%of the corresponding rates in AP patients without AKI,respectively.The factors that influenced the AP patients’survival rate included body mass index(BMI),mean values of IPP,minimum platelet count,and hospital day,of which mean values of IPP showed the greatest impact.CONCLUSION AP patients with AKI had a lower survival rate and worse relevant clinical outcomes than AP patients without AKI,which necessitates further attention to AP patients with AKI in surgical intensive care unit.

Comparison of demographic features and laboratory parameters between COVID-19 deceased patients and surviving severe and critically ill cases

BACKGROUND Coronavirus disease 2019(COVID-19) has been far more devastating than expected, showing no signs of slowing down at present. Heilongjiang Province is the most northeastern province of China, and has cold weather for nearly half a year and an annual temperature difference of more than 60℃, which increases the underlying morbidity associated with pulmonary diseases, and thus leads to lung dysfunction. The demographic features and laboratory parameters of COVID-19 deceased patients in Heilongjiang Province, China with such climatic characteristics are still not clearly illustrated.AIM To illustrate the demographic features and laboratory parameters of COVID-19 deceased patients in Heilongjiang Province by comparing with those of surviving severe and critically ill cases.METHODS COVID-19 deceased patients from different hospitals in Heilongjiang Province were included in this retrospective study and compared their characteristics with those of surviving severe and critically ill cases in the COVID-19 treatment center of the First Affiliated Hospital of Harbin Medical University. The surviving patients were divided into severe group and critically ill group according to the Diagnosis and Treatment of New Coronavirus Pneumonia(the seventh edition).Demographic data were collected and recorded upon admission. Laboratory parameters were obtained from the medical records, and then compared among the groups.RESULTS Twelve COVID-19 deceased patients, 27 severe cases and 26 critically ill cases were enrolled in this retrospective study. No differences in age, gender, and number of comorbidities between groups were found. Neutrophil percentage(NEUT%), platelet(PLT), C-reactive protein(CRP), creatine kinase isoenzyme(CK-MB), serum troponin I(TNI) and brain natriuretic peptides(BNP) showed significant differences among the groups(P = 0.020, P = 0.001, P < 0.001, P = 0.001, P < 0.001, P <0.001, respectively). The increase of CRP, D-dimer and NEUT% levels, as well as the decrease of lymphocyte count(LYMPH) and PLT counts, showed significant correlation with death of COVID-19 patients(P = 0.023, P = 0.008, P = 0.045, P = 0.020, P = 0.015, respectively).CONCLUSION Compared with surviving severe and critically ill cases, no special demographic features of COVID-19 deceased patients were observed, while some laboratory parameters including NEUT%, PLT, CRP, CK-MB, TNI and BNP showed significant differences. COVID-19 deceased patients had higher CRP, D-dimer and NEUT% levels and lower LYMPH and PLT counts.

Phacoemulsification combined with transpupillary removal of silicone oil and intracapsular intraocular lens implantation

AIM： To estimate the effectiveness of phacoemulsification and foldable intraocular lens（IOL） implantation combined with transpupillary silicone oil removal.METHODS： There were 168 eyes of 168 candidate patients with cataract and silicone oil-filled eyes recruited in our study. All of the patients received the intraocular silicone oil removal surgery by transpupillary drainage and cataract extraction by phacoemulsification. Then the IOL implantation were also performed through corneal incision. RESULTS： The surgery was successfully completed in all eyes. Best corrected visual acuity（BCVA） and postoperative complications were recorded in three months after surgery. There were 143 eyes with BCVA improved, otherwise 25 eyes remained stable at the last follow-up visit. The mean BCVA statistically improved from 20/400±0.02 to 20/100±0.15（P〈0.001） and mean postoperative IOP was 13.85±2.18 mm Hg（P=0.415）. No intra-operative complications were reported.CONCLUSION： Phacoemulsification combined with transpupillary removal of silicone oil is a safe and simple effective method. In general, it enables quick recovery of visual acuity with less complication rate.

Genes encoding a group of related small secreted proteins from the gut of Hessian fly larvae [Mayetiola destructor （Say）]

A group of related genes has been isolated and characterized from the gut of Hessian fly larvae [Mayetiola destructor （Say）]. Members in this group appear to encode proteins with secretary signal peptides at the N-terminals. The mature putative proteins are small, acidic proteins with calculated molecular masses of 14.5 to 15.3 kDa, and isoelectric points from 4.56 to 4.88. Northern blot analysis revealed that these genes are expressed predominantly in the gut of Hessian fly larvae and pupae. Two related genes, GIOK1 and GIOK2, were isolated as tandem repeats. Both genes contain three exons and two introns. The intron/exon boundaries were conserved in terms of amino acid encoding, suggesting that they arose by gene duplication. The fact that the frequency of this group of clones in a gut cDNA library higher than that of total cDNA clones encoding digestive enzymes suggested that this group of proteins may perform an important function in the gut physiology of this insect. However, the exact functions of these proteins are as yet known since no sequence similarity could be identified between these proteins and any known sequences in public databases using standard methods.

A Single-wavelength NIR-triggered Polymer for in Situ Generation of Peroxynitrite (ONOO^(−)) to Enhance Phototherapeutic Efficacy

Phototherapies including photodynamic therapy(PDT)and photothermal therapy(PTT)are the most promising and non-invasive cancer treatments.However,the efficacy of mono-therapy of PDT or PTT is often limited by the phototherapeutic defects such as low light penetration depth of photosensitizers and insufficiency of photothermal agents.Peroxynitrite(ONOO−)has been proved to be an efficient oxidizing and nitrating agent that involves in various physiological and pathological processes.Therefore,ONOO−produced in tumor site could be an effective treatment in cancer therapy.Herein,a novel cyanine dye-based(Cy7)polymer nanoplatform is developed for enhanced phototherapy by in situ producing ONOO−.The Cy7 units in the nanoparticles can not only be served as the photosensitizer to produce reactive oxygen species(ROS)including singlet oxygen and superoxide anion for PDT,but also be used as a heat source for PTT and the release of NO gas from N-nitrosated napthalimide(NORM)at the same time.Since NO can react quickly with superoxide anion to generate ONOO−,the enhanced phototherapy could be achieved by in situ ONOO−produced by PCy7-NO upon exposure to the near infrared(NIR)light.Therefore,the NIR-triggered Cy7-based nanoplatform for ONOO−-enhanced phototherapy may provide a new perspective in cancer therapy.

Susceptibility of field populations of sugarcane borer from non-Bt and Bt maize plants to five individual Cry toxins

Sugarcane borer, Diatraea saccharalis （E）, is a major target of transgenic maize expressing Bacillus thuringiensis （Bt） proteins in South America and the US mid- south region. Resistance development in target pest populations is a major threat to the sustainable use of Bt crops. In our field trials in 2009, a significant number of live borers and plant injury fi＇om D. saccharalis were observed in an experimental SmartStaxTM maize line. The objective of this study was to assess the relative susceptibility of two field popula- tions ofD. saccharalis collected from non-Bt and Bt maize plants containing SmartStaxTM traits to five individual Cry proteins. The five Bt proteins included two proteins （Cry 1A. 105 and Cry2Ab2） that were expressed in SmartStaxTM maize plants and three other common Bt proteins （Cry 1Aa, Cry 1Ab and Cry l Ac） that were not produced in SmartStaxTM. Larval mortality and growth inhibition on Bt diet of the fourth generation after field collections were evaluated 7 days after release of neonates on the diet surface. The laboratory bioassays showed that 50% lethal concentration （LCs0） values for CrylA. 105 and Cry2Ab2 for the population originated from Bt plants were 3.55- and 1.34-fold greater, respectively, than those of the population collected from non-Bt plants. In contrast, relative to the popula- tion from non-Bt plants, the LCs0 of the population sampled from Bt plants were 3.85-, 2.5- and 1.64-fold more sensitive to CrylAa, CrylAb and CrylAc, respectively. The re- sults did not provide clear evidence to conclude that the observed field survival of D. saccharalis on Bt plants was associated with increased levels of resistance.